This invention relates to the field of data recording and playback. More particularly, it relates to improvements in protective cartridges used to house data storage disks, such as optical, magneto-optical and magnetic disks.
Most conventional high density recording systems use data storage disks to store vast quantities of information in binary form. Owing to the high packing density of the stored bits of information, it is essential that the data-recording surfaces of these disks be protected from dirt, dust and other debris which can either obscure recorded bits or interfere with the recording of such bits. A variety of protective enclosures, referred to in the art as "cases," "cassettes," "cartridges," "caddies," etc., have been designed with this purpose in mind. The structural design and appearance of these cartridges is usually determined by the features of the disk drive units in which they are to be used. For example:
U.S. Pat. No. 4,433,410 (Siryi et al) discloses an optical disk cartridge which is intended for use in a disk drive unit of the type which includes means for rotating the disk within the cartridge. The cartridge comprises a plurality of spring loaded fingers which engage the rim of the disk and prevent the information-bearing surfaces from touching the inside surfaces of the cartridge. Upon being engaged by certain "pins" in the disk drive unit, the spring-loaded fingers are separated from the disk rim, thereby allowing the disk to rotate within the cartridge. A central circular aperture formed in the cartridge allows a spindle to engage the disk for rotation, and a radially extending slot or window allows an optical transducer to access all of the information tracks as the disk rotates.
In the commonly assigned U.S. Pat. No. 4,853,926 (Covington et al), a data storage disk is protectively packaged by a caddy/carrier assembly. The caddy is merely a temporary container for the disk during periods of non-use. The carrier comprises a rectangular frame which fits within the caddy and serves to support the disk at several locations along the disk's rim. A side wall of the caddy is provided with a pair of spring-loaded doors through which a disk-extracting mechanism of a suitable disk drive unit can enter and extract the disk/carrier assembly for utilization. Upon removing the disk/carrier assembly from the caddy, the disk is released from the carrier frame (by another disk drive mechanism), and the disk is loaded onto a spindle for rotation. After use, the disk is returned to the carrier frame, and the disk/carrier assembly is returned to the protective caddy through the caddy doors.
From the foregoing, it may be appreciated that the protective package surrounding a data storage disk determines the type of disk drive unit with which it can be used. Certainly, disks housed by cartridges of the type disclosed by Siryi et al cannot be used in the disk drive units designed to accept the Covington et al carrier/caddy assembly, and vice versa.